Travellers in a foreign country who do not speak the local language typically rely on conventional printed phrase books to be able to communicate with the natives of said foreign country. Flipping through the pages of a phrase book to find a desired phrase, however, can be frustrating for both the speaker and the listener, both of whom are accustomed to considerably faster conversational rates. In addition, once the speaker finds the desired phrase in the phrase book, said speaker may experience difficulty in pronouncing the phrase in a comprehensible way.
The aforementioned shortcomings of printed phrase books have led to the development of electronic phrase books or translation devices, which allow the user to directly enter a phrase to be translated either via a hand-operated input device, such as a keyboard, or by speaking into a microphone connected to a speech-recognition system. Regardless of the input device being utilized, the user is able to directly specify the phrase to be translated, thereby relegating to the translation device the tedious chore of looking up the phrase in a translation table. In addition, certain electronic translation devices include means for reading their translations aloud via a speech-synthesis system connected to a loudspeaker, thereby alleviating any potential difficulties on the part of the user in pronouncing the phrases intelligibly. One example of an electronic phrase book is the Voice Language Translator described by Rondel et al. in U.S. Pat. No. 4,984,177, granted Jan. 8, 1991. This voice language translator includes means for recognizing a phrase spoken by the user, for looking up the phrase in a translation table, and for speaking aloud the resulting translation of the phrase.
It is important to realize, however, that all existing phrase books, whether printed or electronic, suffer from a common, severe flaw: they often fail to contain the phrases that users wish to say. For example, one may find oneself in a department store in a foreign country, and in search of a cash register at which to make one's purchase; but few phrase books provide a translation for the natural phrase to utter in this context, namely, "Where's the nearest cash register?". A multitude of other seemingly natural phrases are absent from surprisingly many phrase books, such as, "Where is the nearest ATM?", "Is it on the Star system?", "Do you have change for a 100-franc note?", "Is there a gym nearby?", "How much is a weekly pass?", "Do you have skim milk?", "How do I get to the Olympic Village?", "What time do the games start?", and so on. From the point of view of the author of the phrase book, it is extremely difficult to correctly anticipate the most common, say, 1000 phrases that travellers will need. The difficulty stems from two sources: first, it is difficult to predict what sorts of activities and artifacts travellers generally talk about. Second, travellers' communicative needs change over time, particularly in the face of new events, such as the Olympics, and new tourist attractions, such as a new Disney theme park.